Lamp mount and component therefor



Oct. 5, 1965 R. L. VlLE LAMP MOUNT AND COMPONENT THEREFOR Filed Oct. 16

FIG.3.

FIG. I.

FIG 4.

FIG. 5.

INVENTOR.

ROBERT Lv VlLE.

United States Patent 3,210,587 LAMP MOUNT AND COMPONENT THEREFOR RobertL. Vile, Perth Amboy, NJ, assignor to Westinghouse Electric Corporation,Pittsburgh, Pa, a corporation of Pennsylvania Filed Oct. 16, 1962, Ser.No. 230,936 Claims. (Cl. 313-271) This invention relates to electricaldevices and has particular reference to a filament mount and a unitaryfilament-bridge assembly for an electric incandescent lamp.

In the manufacture of electric incandescent lamps the ends of thefilament are supported by and connected directly to the lead-inconductors either by clamping or welding the members together. In thecase of large lamps rated at 300 watts or above having coiled coils, theconductors are attached to the singly-coiled end sections of thefilament and means must be provided to prevent them from becomingcrushed or broken during the welding or clamping operation. This wasaccomplished in the prior art by fashioning so-called inserts consistingof short pieces of molybdenum wire or the like bent to very closetolerances so as to make a tight fit with the coiled end sections. Theseinserts were manually placed into the end sections before the latterwere joined to the lead-in conductors and served as a sort of mandrelthat prevented the coil turns from collapsing while being clamped orwelded. The inserts had to be carefully formed and loaded into thecoiled ends of the filament in order to lock them in place while thefilament was being mounted on and fastened to the lead-in conductors.

When mounting such large coiled-coil filaments it is also necessary toprovide some means of supporting the medial portion of the filament toprevent the latter from sagging excessively or breaking under shock orvibration conditions. This requirement was met in the prior art mountstructures by bridging the lead-in conductors with wires joined by aninsulator, and then anchoring an auxiliary support wire in theinsulator. The use of such bridge assemblies and separate coil insertswas not only costly from a material standpoint but made the assembly ofthe mount a complicated operation that slowed down production andincreased the manufacturing cost of the lamps.

It is, accordingly, the general object of the present invention toprovide an improved mount structure for supporting an energizablecomponent within an electrical device such as an electric lamp or thelike.

Another object is the provision of a filament mount for an electric lampthat is rugged, simple to make and requires a minimum amount ofmaterial.

Still another object is the provision of a filamentbridge assembly thatcan be fabricated as a separate unit that is capable of beingconveniently handled and attached directly to the lead-in conductors ofa lamp stem.

The foregoing and other objects and advantages which will become obviousto those skilled in the art are achieved in accordance with the presentinvention by utilizing the end portions of the bridge wires as the coilinserts. This is accomplished by bending end segments of the bridgewires to form offset leg portions that are adapted to interlock with thecoiled end sections of the filament in the same manner as the separatecoil inserts used heretofore. The opposite ends of the bridge wires areembedded in a glass insulator together with an auxiliary support wirewhich is coupled to the central portion of the filament. When thusassembled, the aforesaid members form an integral filament-bridgeassembly that can be conveniently handled and attached as a separateunit to the lead-in conductors of the lamp stem.

Thus, the bridge structure according to the present invention comprisesa dual-purpose component that functions both as a coil insert and as anauxiliary support means for the filament.

A better understanding of the invention will be obtained from theaccompanying drawing, wherein:

FIGURE 1 is a front elevational view of a lamp mount according to oneembodiment of the invention;

FIG. 2 is a side elevational view of the upper portion of the mount asviewed along the reference line IIII of FIG. 1, in the direction of thearrows;

FIG. 3 is a front elevational view of the V-shaped coiled-coil filamentshown in the preceding figures;

FIG. 4 is a perspective view of the bridge component used in thefilament-bridge assembly shown in FIGS. 1 and 2;

FIG. 5 is a similar view of the completed filamentbridge assembly in thefinal stage of fabrication; and

FIGS. 6 to 8 are elevational and perspective views of other types offilament-bridge assemblies according to the invention.

Although the dual-purpose bridge structure and subassernbly technique ofthe present invention can be used with advantage in the manufacture ofvarious types of electrical devices, it is especially adapted for use inmounting coiled-coil incandescent lamp filaments having a rating of 300watts and above and has, accordingly, been so illustrated and will be sodescribed.

EMBODIMENT I In FIGS. 1 and 2 there is shown one embodiment of a mount10 for a 750 watt incandescent lamp according to the present invention.As illustrated in FIG. 1, the mount consists of the usual glass flare 12having an axially extending exhaust tube 14 depending from one end and apress 15 at its opposite end that is hermetically sealed around andsupports a pair of lead-in conductors 16 and 18 in upstandingspacedapart relation. The ends of the conductors above the press areflared outwardly to provide a pair of divergent end segments 17 and 19,respectively, which are fastened as by welding or the like topreselected portions of the unitary filament-bridge assembly 20 of thepresent invention.

According to the particular embodiment of the invention shown in FIGS. 1and 2, the aforesaid unitary filament-bridge assembly consists of aV-shaped coiled-coil tungsten filament 22 having a centrally locatedopen turn or bight 23 and axially extending singly'coiled end sections24 and 25 that are substantially straight and include a plurality ofturns. The filament 22 is held in place on the mount 10 by a pair ofL-shaped bridge wires 26 and 28, the short segments whereof constitutewhat will be hereinafter called offset leg portions 27 and 29,respectively. These leg portions extend into and are so dimensioned thatthey frictionally engage the substantially straight end sections 24 and25 of the filament 22 and thus eifect an interlocking juncturetherewith.

The opposite ends of the bridge wires 26 and 28 are embedded in aninsulator 34 of suitable vitreous material, such as hard glass or thelike. The bridge wires and filament are thus joined or tied together bythe insulator and form a unitary filament-bridge assembly 20 that can bemade and handled as a separate unit, and subsequently attached to thelead-in conductors. Also embedded in the insulator is an auxiliarysupport wire 30 which, as shown most clearly in FIG. 2, extends upwardlyfrom the insulator 34 and to one side of the filament 22 and has alaterally extending arm 31 with a hook 32 formed at its end that isclosed around the bight 23 of the filament.

As will be noted from FIG. 1, the L-shaped bridge support wires 26 and28 are so oriented that the ends thereof opposite the offset legportions 27 and 29 are located proximate and substantially perpendicularto one another. Thus, the filament 22 and bridge component (that .is,theconjoined bridge wires 26 and 28, the support wire 30, and insulator 34illustrated in FIG. 4) are so arranged that the filament-bridge assembly20 comprises a generally rectangular structure in which the insulator islocated diagonally opposite the bight portion 23 of the filament (seeFIG. 1) and all the elements, except for the auxiliary support 30, liein substantially the same plane (see FIG. 2).

The bridge wires 26 and 28 and the auxiliary support wire 30 are, ofcourse, fabricated from a suitable refractory metal such as molybdenumthat will withstand the extreme temperatures that prevail within thelamp when the filament is energized.

As shown in FIGS. 1 and 2, the flared end segments 17 and 19 of thelead-in conductors 16 and 1.8, respectively, extend across both legs ofthe bridge wires 26 and 28 proximate the right angle bends therein andare fastened to the filament-bridge assembly 20 at the junctures betweenthe offset leg portions 27 and 29 and the coil end sections 24,and 25.They may be fastened either by welding, as here shown, or by clamping sothat the lead-in conductors are mechanically and electrically joined toboth the bridge wires and the overlying turns of the filament. It hasbeen found that a stronger mount can be obtained by welding or otherwisefastening the lead-in conductors 16 and 18 to the respective bridgewires 26 and 28 at their second point of intersection (points 33 and 35shown in FIG. 1) which is remote from the offset leg portions andlocated between these portions and the insulator 34-.

As shown in FIG. 3, the filament 22 as fabricated is V-shaped anddimensioned to nestingly interlock with the bridge component shown inFIG. 4. To mount the filament the coiled end sections 24 and 25 aresimply slipped over the offset leg portions 27 and 29 so that thefilament bight 23 lays in the support hook 32, as illustrated in FIG. 5,thereby forming the unitary filamentbridg-e assembly 20. The hook 32 isthen closed (as indicated by the dotted portion of FIG. to lock thefilament 22 in place and complete the fabrication of the assembly whichcan then be handled and fastened to the lead-in conductor-s as aseparate subassembly without coming apart.

EMBODIMENT II In FIG. 6 there is shown another filament-bridge assembly20a that is substantially the same as the one above described exceptthat the offset leg portions 27a and 29:: are of arcuate configurationrather than straight. The curvature of the offset leg portions is suchthat they are slightly convex inwardly toward .the upstanding auxiliarysupport arm. Upon being forcibly slipped over the curved leg portionsthe end sections 24a and 25a of the coiled-coil filament 22a aredisplaced from their normally straight configuration. The resultingdeformation of these coil end sections imparts a stress to the adjoiningunsupported portions of the filament that causes the coil barrel to bowoutwardly and assume an arched configuration, as illustrated in FIG. 6.The stressed filament is, accordingly, rigidified and made moreresistant to sag. A detailed discussion of this phenomenon is set forthin US. Patent No. 2,924,735 of J. Martin, dated February 9, 1960 andowned by the assignee of the present invention.

The aforesaid prestressed filament-bridge assembly 20a is rigidlyfastened to the lead-in conductors 16a and 18a, shown in dotted outlinein FIG. 6, in the same manner as described previously.

EMBODIMENT III In FIG. 7 there is shown another embodiment of thepresent invention wherein a unitary filament-bridge assembly 20b isprovided which is adapted to accommodate a coiled-coil filament 22b oflinear configuration having a centrally located open turn 23b andsubstantially straight axially-extending singly-coiled end sections 24band 25b. According to this embodiment, the bridge wires 26b and 231) areprovided with two right angle bends that are so located that the offsetleg portions 27b and 2% are substantially coaxial with the filament endsections and the opposite end portions of the wires parallel withfilament and terminate at a point opposite the open turn 23b where theyare joined by a glass insulator 34b. The auxiliary support wire 30]) inthis case constitutes a straight piece of wire that is looped around theopen turn 23b and extends laterally to the insulator.

The insulator, the bridge and support wires, and the filament thus alllie in approximately the same plane according .to this embodiment. Thefilament can be supported in the desired coaxial relationship with thestem by fastening the assembly 2017 at four points to suitably formedlead-in conductors 16b and 18b, such as those shown in dotted outline inFIG. 7.

EMBODIMENT IV In FIG. 8 there is shown another embodiment for axiallymounting a coiled-coil filament 22c having coiled end sections 240 and25c which extend transversely with respect to the coil body or filamentaxis. As there shown, the unitary filament-bridge assembly 200 issimilar to the assembly shown in FIG. 7 except that the offset legportions 270 and 29c are so formed that they extend laterally of thefilament axis and are aligned with transversely extending coiled endsections of the filament. Thus, in this case, the insulator and theportions of the bridge wires which it joins lie in a plane that isgenerally perpendicular to the filament plane. However, by suitablybending and fastening the lead-in conductors 16c and (shown in dottedoutline in FIG. 8) to the filament-bridge assembly 20c and using adiagonally oriented auxiliary support wire 300, this type of filamentcan also be very conveniently and securely supported in axiallyextending relationship with the stem and lamp.

Summary It will be apparent from the foregoing that employing a bridgestructure that serves both as a coil insert and as an auxiliaryfilament-supporting means in accordance with the present inventionreduces the number of parts and operations required to mount thefilament and, thus, materially decreases the manufacturing cost of thelamp. In addition, the aforesaid dual-purpose bridge structure enablesthe filament to be assembled with the bridge in a separate operation toform a unitary filament-bridg assembly that can be readily handled andquickly attached to the ends of the lead-in conductors thereby improvingthe quality of the mounts and further facilitating their fabrication.

Since the lead-in conductors can very readily be welded rather thanclamped to the filament-bridge assembly, the ends of the conductors donot have to be flattened and formed into clamps as was the caseheretofore. The conductors can, accordingly, be made of harder material(nickel-plated iron, for example, instead of the soft nickel generallyused) thus further improving the shock-resistant properties of themounts.

While several embodiments have been illustrated and described, it willbe obvious to those skilled in the art that various modifications inboth the configuration and arrangement of parts can be made withoutdeparting from the spirit and scope of the invention.

I claim:

1. A mount for an electric lamp or the like comprising;

a coiled filament,

a pair of bridge wires each having an offset leg portion at one end atleast a part of which extends into and engages the respective ends ofsaid filament,

6 a vitreous insulator joining the opposite ends of said other of saidleg portions at the point at which they bridge wires and therebycoupling said bridge wires intersect, and and filament together into aunitary assembly. a stem having a press that is hermetically sealedaround a pair of lead-in conductors having end segments that saidlead-in conductors and holds them in upstandare fastened to the offsetleg portions of the respec- 5 ing position. tive bridge wires and toanother portion of said wires 4. The incandescent lamp mount set forthin claim 3 remote from said leg portions and located between wherein;said leg portions and said insulator, and said filament is V-shaped, avitreous stem sealed to said lead-in conductors and said bridge wiresare arranged to form a generally recholding them in upstandingsupporting relationship 10 tangular structure with said filament, andwith said unitary assembly. said insulator is located diagonallyopposite the apex 2. A mount for an electric lamp or the like as setforth of said filament. in claim 1 wherein said lead-in conductors arefastened 5. The incandescent lamp mount set forth in claim 3 to theparts of the respective offset leg portions of said wherein; 'bridgewires located within the filament and are also fassaid filament is oflinear configuration and the singlytened to the overlying turns of saidfilament. coiled end sections thereof extend in a direction trans- 3. Amount for an electric incandescent lamp comverse to the filament axis,and prising; the leg portions of said bridge wires joined to said filaacoiled-coil filament of refractory Wire having a singlyment are offsetand lie in a different plane than said coiled section at each end,insulator and the legs of said bridge wires which it a pair of L-shapedbridge wires each having one of its joins.

leg portions located within and frictionally interlocked with therespective singly-coiled end sections References Cited y the Examiner ofsaid filament so as to form a juncture therewith, UNITED STATES PATENTSsaid bridge wires being so arranged that the ends thereof opposite theleg portions joined to said filament 2116384 5/38 Cal-mm 313 316 X2,848,642 8/58 WlSCO et al 313-344 X lie proximate one another, 2 877375 3/59 P 313 315 a glass insulator joining the proximate ends of saidCarson Q 2,910,611 10/59 Jordan et a1 313--315 X bridge wires and tyingsaid wires and filament into a 2,924,735 2/60 Martin 3133 15 X umtaryfilament bridge assembly. 3 007 074 10/61 S 1 3 2 a pair of spacedlead-in conductors having divergent wasey et a 31 79 end segments thatextend across both of the leg FOREIGN PATENTS portions of the respectivebridge wires proximate the bends therein and are welded to the endsections of said filament and to the leg portions located there- 35 inand thus support said filament-bridge assembly, DAVID GALVIN PrlmmyExammer' each of said lead-in conductors being fastened to the JAMESKALLAM, Examiner- 7l4,761 9/54 Great Britain.

1. A MOUNT FOR AN ELECTRIC LAMP OR THE LIKE COMPRISING; A COILEDFILAMENT, A PAIR OF BRIDGE WIRES EACH HAVING AN OFFSET LEG PORTION ATONE END AT LEAST A PART OF WHICH EXTENDS INTO AND ENGAGES THE RESPECTIVEENDS OF SAID FILAMENT, A VITREOUS INSULATOR JOINING THE OPPOSITE ENDS OFSAID BRIDGE WIRES AND THEREBY COUPLING SAID BRIDGE WIRES AND FILAMENTTOGETHER INTO A UNITARY ASSEMBLY, A PAIR OF LEAD-IN CONDUCTORS HAVINGEND SEGMENTS THAT ARE FASTENED TO THE OFFSET LEG PORTIONS OF THERESPECTIVE BRIDGE WIRES AND TO ANOTHER PORTION OF SAID WIRES REMOTE FROMSAID LEG PORTIONS AND LOCATED BETWEEN SAID LEG PORTIONS AND SAIDINSULATOR, AND